Recently, portable terminals with novel functions have been developed rapidly, and as the distribution of the portable terminals has expanded, the portable terminals are representing a gradually increasing share of people's lives.
Alternatively, portable terminals (e.g., a smart phone) that have been popularized with the development of the mobile communication technology adapt various keys that are provided on the front face, the rear face, and the side face thereof.
Further, as users' needs for portable terminals have been gradually diversified, a key used in the portable terminals includes a waterproof structure in order to prevent a fluid from infiltrating into the interior of the portable terminals.
A home key waterproof structure using a fingerprint recognition sensor that is used in a portable terminal is manufactured in a structure to be fixed to a key bracket by insert-molding a flexible printed circuit board in a home key mold. However, the home key waterproof structure is formed in a structure through which the flexible printed circuit board passes to the outside of the key bracket so that indentations are generated in a sealing member region for waterproof. The indentations have irregular shapes and considerably deteriorate the sealing effect, which causes a high percentage of defects and makes the waterproof function instable. Alternatively, due to a structure in which a plurality of components are stacked in multiple tiers on the top and bottom faces of the flexible printed circuit board, a key click feeling is considerably degraded.